Improve error message when parsing output of `ip netns pids`

This is very unlikely to fail but debugging such errors is painful
without the original output.

diff --git a/main.go b/main.go
index 08c9a563155f2f38b5625aaf08d883e105b11236..0cf8c848ada973494ff3478dfcd5c8d25fa468b0 100644 (file)
--- a/main.go
+++ b/main.go
@@ -176,7 +176,7 @@ func netnsPids(netns string) []int {
        for _, x := range xs {
                y, err := strconv.Atoi(x)
                if err != nil {
-                       log.Fatal(err)
+                       log.Fatalf("invalid output from %q: %q: %v", xargs, out, err)
                }
                res = append(res, y)
        }